[Proj] Re: Proj Digest, Vol 42, Issue 8

[Jordi Gilabert Vall]

I use these 7 coefficients with cartography in Catalonia (Spain), with right
results:

cs2cs +proj=latlong +datum=WGS84 +ellps=WGS84 +to +init=epsg:23031 +proj=utm
+ellps=intl +zone=31 +units=m +towgs84=- 131.0320,-100.2510,-163.3540,1.2438
,0.0195,1.1436,9.3900

More information:

http://www.euref-iag.net/symposia/book2003/4-6.pdf<http://www.fomento.es/NR/rdonlyres/8B4D8323-5706-4F8F-84F7-C89774DCC2A1/29826/hercam.pdf>
http://www.fomento.es/NR/rdonlyres/8B4D8323-5706-4F8F-84F7-C89774DCC2A1/29826/hercam.pdf


Jordi Gilabert Vall

----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 29 Nov 2007 14:55:17 +0100
> From: Roger Oberholtzer <roger at opq.se>
> Subject: RE: [Proj] WGS84 to ED50
> To: "PROJ.4 and general Projections Discussions"
>         <proj at lists.maptools.org>
> Message-ID: <1196344518.25474.84.camel at acme.pacific>
> Content-Type: text/plain; charset=UTF-8
>
> I have a bit more information on the problem with WGS84 lat/longs ->
> ED50(Spain) northings and eastings.
>
> The software that is being used does not have a 'Spanish' setting. So
> they have defined an ED50 7 parameter transform, with these
> coefficients:
>
>
> > International Ellipsoid 1924 definition
> > Mayor semiaxle: 6378388
> > Minor semiaxle:6356911,9461
> > 1/f:297
> > Excentricity: 0.0819910890032286
> >
> > About the 7 parameters transformation
> > Translation X (m): 125.098545
> > Translation Y (m): 76.000054
> > Translation Z (m): 156.198703
> > X Rotation(seconds): 0
> > Y Rotation(seconds): 0
> > Z Rotation(seconds): -1.129
> > Scale factor (ppm): -8.30463103
> >
> > This correspond with applanix header file saying
> > Mapping frame datum: ED50_ESPAÑA ; a = 6378388.000000; 1/f = 297.000000;
> >  Coordinate transformation from WGS84 to mapping frame datum
> >     dX = 125.098545; dY = 76.000054; dZ = 156.198703; f = 0.999991695369
> ;
> >     R1 = 0.000000000000; R2 = 0.000000000000; R3 = -0.000005473550;
> >  sequence of the rotations: x,y,z,1
> >  Mapping frame projection : TM;
> >  central meridian = -3.000000 deg;
> >  latitude of the grid origin = 0.000000 deg; grid scale factor =
> 0.999600:
> >  false easting = 500000.000000 m; false northing = 0.000000 m;
> >
> >
> > Where Rotations are in radians
>
> I have tried setting proj to use this, as reported earlier in this thread,
> with no luck. I tried using the 7 parameters as
> +towgs84=125.098545,76.000054,156.198703,0.0,0.0,-1.129,-8.30463103, but
> that made things worse.
>
> fromProj = pj_init_plus(
>                         "+proj=latlong "
>                         "+ellps=WGS84 "
>                         "+no_defs");
>
> toProj = pj_init_plus(
>                         "+proj=utm "
>                         "+ellps=intl "
>                         "+k=0.999600 "
>                         "+x_0=500000.0 "
>                         "+y_0=0.0 "
>                         "+zone=30 "
>                         "+units=m"
>
> "+towgs84=125.098545,76.000054,156.198703,0.0,0.0,-1.129,-8.30463103"
>                         "+no_defs");
>
> So I am guessing I cannot simply use the 7 parameters as given. Correct?
>
>
>
> --
> Roger Oberholtzer
>
> OPQ Systems / Ramböll RST
>
> Ramböll Sverige AB
> Kapellgränd 7
> P.O. Box 4205
> SE-102 65 Stockholm, Sweden
>
> Office: Int +46 8-615 60 20
> Mobile: Int +46 70-815 1696
>
>
>
> ------------------------------
>
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